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Date: Thu, 12 Jul 2007 09:30:27 +0200
From: Cornelia Huck <cornelia.huck@de.ibm.com>
To: Alan Stern <stern@rowland.harvard.edu>
Cc: Daniel J Blueman <daniel.blueman@gmail.com>,
       Chuck Ebbert <cebbert@redhat.com>,
       Linux Kernel <linux-kernel@vger.kernel.org>,
       USB development list <linux-usb-devel@lists.sourceforge.net>
Subject: Re: [linux-usb-devel] [2.6.22-rc7] khubd NULL deref oops...
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On Wed, 11 Jul 2007 17:41:13 -0400 (EDT),
Alan Stern <stern@rowland.harvard.edu> wrote:

> On Wed, 11 Jul 2007, Daniel J Blueman wrote:
> 
> > > Try disabling CONFIG_USB_SUSPEND.  It makes lots of USB bugs go away
> > 
> > I'll give it a shot. For the record, I wasn't trying to perform a
> > suspend at this time (or since booting).
> 
> I doubt that USB suspend has any connection with this problem.  It's
> clear that the problem occurs in the driver core when the SCSI core
> tries to unregister a device.  It's not directly related to USB at all.

Hm, it seems that the class device's kobject is not set up correctly
(at least, not its name) when make_class_name() is called. Might be
that it is unregistered before it has been added completely (at least,
before kobject_set_name() has been called).

> 
> In fact, it looks like the bug is connected with 
> CONFIG_SYSFS_DEPRECATED.  You can try to see what happens with that 
> switch disabled.

Turning on verbose driver core messages (CONFIG_DEBUG_DRIVER) while
leaving on CONFIG_SYSFS_DEPRECATED may also be worthwile.